What is the BMI of a 170 cm tall, 87.9 kg adult and what weight‑loss management should be recommended?

BMI Calculation and Weight Management Recommendation

This patient has a BMI of 30.4 kg/m², which classifies them as Class I obese, and they require active weight loss treatment through a comprehensive lifestyle intervention program combining caloric restriction, physical activity, and behavioral therapy. 1

BMI Classification

• BMI = 87.9 kg ÷ (1.70 m)² = 30.4 kg/m², which falls into the obesity category (BMI ≥30 kg/m²) 1
• This BMI level is associated with increased risk of cardiovascular disease, type 2 diabetes, hypertension, and mortality 1
• Waist circumference should be measured to provide additional cardiometabolic risk stratification: >102 cm in men or >88 cm in women indicates elevated risk 1

Mandatory Initial Assessment

Before initiating treatment, the following must be evaluated 1:

• Cardiovascular risk factors: Blood pressure, fasting lipid panel, fasting blood glucose to screen for hypertension, dyslipidemia, prediabetes, or diabetes 1
• Weight history: Previous weight loss attempts, patterns of weight gain/loss, dietary habits, physical activity level, family history of obesity 1
• Medications review: Identify any drugs that may contribute to weight gain and consider adjustments 2
• Obesity-related comorbidities: Screen for sleep apnea, fatty liver disease, and other complications 1

Treatment Indication and Goals

• Weight loss treatment is definitively indicated for all individuals with BMI ≥30 kg/m², regardless of the presence of additional risk factors 1
• Target weight loss: 5-10% of initial body weight over 6 months (approximately 4.4-8.8 kg for this patient) 1, 3
• This magnitude of weight loss produces clinically meaningful improvements: reduced triglycerides, blood glucose, HbA1c, blood pressure, and improved LDL-C and HDL-C 3

Dietary Intervention (Cornerstone of Treatment)

Create a daily energy deficit of 500-750 kcal through caloric restriction 3:

• Prescribe 1,500-1,800 kcal/day for men or 1,200-1,500 kcal/day for women 1, 3
• This caloric deficit should produce a weight loss of 0.5-1 kg per week 1, 2
• Macronutrient composition: Total fat 25-35% of energy, saturated and trans fats <7%, with emphasis on vegetables, fruits, legumes, and whole grains 1
• Structured meal plans with portion control or meal replacements are evidence-based options to improve adherence 3, 2
• Eliminate sugary drinks and ultra-processed foods 2

Physical Activity Prescription

Prescribe at least 30 minutes of moderate-intensity endurance exercise five or more days per week, combined with strength training 1, 3:

• Moderate-intensity activities include brisk walking, cycling, or swimming 1, 3
• For individuals with BMI ≥30 kg/m², choose activities that do not burden the musculoskeletal system 1, 4
• Reduce sedentary activities (television watching, computer use) 1
• Physical activity is crucial for long-term weight maintenance, though dietary restriction is more effective for initial weight loss 2

Behavioral Therapy

A minimum of 14-16 intensive behavioral therapy sessions over 6 months is recommended 3, 2:

• Focus on self-monitoring (food diaries, weight tracking), nutrition education, and cognitive restructuring 2
• Behavioral therapy combined with diet and exercise can produce 5-10% weight loss 2
• Maximum weight loss typically occurs between 6-12 months 2

Pharmacotherapy Consideration

If the patient fails to achieve 5-10% weight loss after 3-6 months of intensive lifestyle intervention, add FDA-approved weight-loss medication 1, 3, 2:

• Pharmacotherapy is indicated as adjunct therapy for BMI ≥30 kg/m² (or BMI ≥27 kg/m² with weight-related complications) 1, 3
• Continue medication only if the patient loses ≥5% of initial body weight in the first 3 months or ≥2 kg in the first 4 weeks 1, 3
• GLP-1 receptor agonists (semaglutide, liraglutide) or other approved agents should be considered 2, 4
• Orlistat (120 mg with each fat-containing meal, maximum 3 capsules daily) is an FDA-approved option that requires concurrent multivitamin supplementation at bedtime 5

Bariatric Surgery Threshold

• Bariatric surgery is not yet indicated at BMI 30.4 kg/m² 1, 3
• Surgery becomes a consideration only if BMI reaches ≥35 kg/m² with weight-related complications or ≥40 kg/m² after failed non-surgical interventions 1, 3

Multidisciplinary Care Structure

Obesity must be managed as a chronic disease by a multidisciplinary team 1, 3:

• Primary physician or obesity specialist, dietician/nutritionist, exercise specialist or physiotherapist, and psychologist or behavioral therapist 3
• Regular monitoring of anthropometric measurements at least every 3 months during active weight management 4

Critical Pitfalls to Avoid

• Do not recommend weight maintenance or "avoid weight gain" advice—this patient requires active weight loss intervention, not maintenance 1
• Do not delay treatment—intensive management of any identified cardiovascular risk factors should be instituted immediately, regardless of weight loss efforts 1
• Do not prescribe very-low-calorie diets (<800 kcal/day) or very-low-fat diets (<15% energy from fat) without specialized supervision 1
• Do not expect rapid weight loss—programs promoting slow, steady weight loss (0.5-1 kg per week) are more effective long-term than rapid weight loss approaches 1